Refactor split_at/split_to #663
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The shallow clone call just above always results in the kind being shared so we don't need to assert it here.
we already assert this at the top of the method
We know several things here: 1. self.len <= self.cap, always 2. at <= self.len, asserted at the top of this method 3. after calling shallow_clone, other.cap == self.cap Therefore, at <= self.len <= other.cap.
This method never moves the cursor backward, only advances it forwards. I think reflecting that in the name makes things a bit more clear. I also added explicit safety comments to make it clear why each usage is sound.
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carllerche
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Feb 6, 2024
| other.len = at; | ||
| // SAFETY: We've checked that `at` <= `self.len()` and we know that `self.len()` <= | ||
| // `self.capacity()`. | ||
| self.advance_unchecked(at); |
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Very minor nitpick, but this is unsafe code so I think it might be worth applying. In split_off, you call advance_unchecked first then update cap and len. You reverse it here. Would you mind keeping them the same?
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Yeah, thanks for pointing it out! Made things a little more consistent in b971743. Let me know if that isn't what you meant.
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I did a little refactoring of
split_atandsplit_toto remove some extraneous checks and add some clarity around safety guarantees.Each commit is fairly self-contained, but here are the highlights with some rationale:
lena little more concisely in ea9dd60.split_atandsplit_toare doing redundant bounds checking and comparison that I removed in 851b59b and 8381ab7.set_starttoadvance_uncheckedto better reflect it's usage in c70d6d2. I also added some explicit comments about the safety guarantees of that method and an explanation of why each usage is sound.I'm pretty new to this repo, so if I've missed some rules or norms please let me know. I'll be happy to change things up!